Characterizing Tissue Specific Regulation of Mutant Lamin Protein Degradation

突变核纤层蛋白降解的组织特异性调节特征

• 批准号: 10291884
• 负责人: Thomas Michael Hammond
• 金额: $ 44.29万
• 依托单位: ILLINOIS STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2024-08-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10291884
• 关键词: Adult; Affect; Aging; Biological Assay; Biological Models; Biopsy; Cell physiology; Charcot-Marie-Tooth Disease; Complex; Data; Defect; Disease; Drosophila genus; Drosophila melanogaster; Emery-Dreifuss Muscular Dystrophy; Failure; Gene Expression; Genes; Genetic; Goals; Health; Homologous Gene; Human; Impairment; Lamins; Lead; MAP Kinase Gene; Muscle; Muscular Dystrophies; Mutation; Neurons; Neuropathy; Outcome; Pathway interactions; Patients; Phenotype; Progeria; Proteins; Quality Control; Regulation; Signal Transduction; Specificity; Structure; System; Testing; Tissues; Toxic effect; disease phenotype; disease-causing mutation; experimental study; fly; human disease; insight; muscle aging; muscular structure; mutant; overexpression; p38 Mitogen Activated Protein Kinase; prevent; protein aggregation; protein complex; protein degradation; proteostasis; therapeutically effective

Project Summary Laminopathies are a wide range of disorders that include both multisystem disorders such as the aging disorder Hutchinson Guilford Progeria and tissue specific disorders such as Emery-Dreifuss Muscular Dystrophy and the neuropathy Charcot-Marie-Tooth disease. All of these different disorders can be caused by mutations in the LMNA gene, however, how mutations in one gene give rise to such different disorders is incompletely understood. Mutant forms of lamin protein have been found to aggregate, and this aggregation is associated with impaired cellular function and disease phenotypes. Therefore, we hypothesize that certain tissues are susceptible to specific lamin mutations due to the inability of tissue specific quality control mechanisms to degrade those mutant forms, leading to protein aggregation and cellular toxicity. We will test this hypothesis using the fruit fly Drosophila melanogaster as our model system. Drosophila allow us to manipulate gene expression in specific tissues, enabling experiments to tease apart how different lamin protein mutations are degraded in specific tissues. Flies have two homologues of the human LMNA gene, LamC and Lam Dm0, and mutations in these genes mimic human disorders. In addition, introducing the equivalent mutations that cause human disease into LamC results in lamin protein aggregation and disease-like phenotypes. Furthermore, AMPK signaling, which is downregulated in muscle biopsies from patients, has been found to reduce mutant LamC aggregation in the fly muscle. On the other hand, we find that Lam Dm0 aggregates in the muscle during aging, and that p38 MAPK (p38Kb) and the CASA complex regulate the degradation of Lam Dm0. One difference between LamC and Lam Dm0 is that while with both lamins are expressed in muscle, only Lam Dm0 is expressed in neurons. As LamC and Lam Dm0 have different tissues specificities, we can also assess if specific protein quality control mechanisms are able to target certain mutant forms of lamin in each tissue. This will allow us to determine if disease tissue specificity is due to the failure of protein quality control machinery to degrade certain mutant forms of lamin protein, resulting in muscular dystrophy rather than neuropathy, for example. Therefore, we will 1) determine if p38Kb and the CASA complex regulate the aggregation of specific forms of mutant LamC proteins and how this contributes to muscle defects, 2) characterize how specific disease mutations in Lam Dm0 affect aggregation in muscles and neurons, and 3) determine if AMPK and p38Kb act in the same or different pathways to regulate mutant lamin aggregation. We expect that our proposed study will provide new insights into how mutant forms of lamin result in a disease state and if activating different protein quality control mechanisms could prove to be an effective therapeutic mechanism.

项目摘要 椎板病是多种疾病，包括两个多系统疾病，例如衰老 疾病Hutchinson Guilford progeria和组织特异性疾病，例如Emery-Dreifuss肌肉 营养不良和神经病charcot-marie-tooth病。所有这些不同的疾病可能是由 然而，LMNA基因中的突变如何引起一种不同的疾病 不完全理解。已发现层状蛋白的突变形式是聚集的，这种聚集是 与细胞功能和疾病表型受损相关。因此，我们假设这是确定的 由于组织特异性质量控制无法 降解这些突变形式的机制，导致蛋白质聚集和细胞毒性。我们将测试 该假设使用果蝇果蝇（果蝇）作为我们的模型系统。果蝇让我们 操纵特定组织中的基因表达，使实验能够嘲笑不同的层粘连蛋白 突变在特定组织中降解。苍蝇具有人类LMNA基因，LAMC和 LAM DM0和这些基因中的突变模仿人类疾病。另外，引入等效物 导致人类疾病进入LAMC的突变导致层质蛋白聚集和疾病样 表型。此外，在患者的肌肉活检中被下调的AMPK信号一直是 发现可以减少蝇肌中突变的LAMC聚集。另一方面，我们发现LAM DM0 衰老期间肌肉的聚集体，p38 MAPK（p38kb）和Casa复合物调节 LAM DM0的降解。 LAMC和LAM DM0之间的一个区别是，两种层粘连是 在肌肉中表达，仅在神经元中表达LAM DM0。由于LAMC和LAM DM0具有不同的组织 特异性，我们还可以评估特定的蛋白质质量控​​制机制是否能够靶向某些突变体 每条组织中的层粘连蛋白的形式。这将使我们能够确定疾病组织特异性是否是由于 蛋白质质量控​​制机制可降解某些突变形式的层粘连蛋白，从而导致肌肉 例如，营养不良而不是神经病。因此，我们将1）确定p38kb和casa是否是 复杂调节特定形式的突变型LAMC蛋白的聚集，以及这如何有助于 肌肉缺陷，2）表征LAM DM0的特定疾病突变如何影响肌肉的聚集 神经元，以及3）确定AMPK和P38KB是否在相同或不同的途径中起作用以调节突变层蛋白 聚合。我们预计我们的拟议研究将提供有关层状突变形式如何结果的新见解 在疾病状态下，如果激活不同的蛋白质质量控​​制机制，可能被证明是有效的 治疗机制。